How Long To Let An 11 Month Old Cry It Out?

I think what you are doing is fine. You've already tried everything else, and he is just fighting sleep. If his crying is slowing down, I would just wait. There's a good chance he'll fall asleep soon. If the crying picks up and gets frantic, then go in and try nursing him again. If you do this consistently, pretty soon you'll be able to nurse him, lay him down in his crib, and he'll just go to sleep on his own. It is important to have a settle-down routine first (you can't take a kid straight from playing and expect him to lay down and sleep immediately, no matter how tired he is), and breastfeeding is a great way to do that.